[he] was fanatically devoted to the fight against realism and to all avant-garde movements. Very typically---and like many of his contemporaries---he hardly distinguished between Expressionism, Cubism, Futurism and abstract art; in fact, he was inclined to call them all Expressionism. What mattered to him was that works of art should be "the expression of a vision", or "the realization of an emotion by the means of painting", and he attached great importance to the "autonomous life of the picture".